Augers are commonly used to convey materials in industrial applications. Applications for augers are as varied as forcing molten materials through an extruder, or filling a container with solids for transport. Unsurprisingly, auger designs may vary considerably depending on the application. FIGS. 1, 2, 3, and 4 illustrate four examples of different auger designs and highlight some of the variety of auger features that may be manipulated. In FIG. 1, auger flights 5 are configured such that when the auger shaft 8 is rotated, the rotating action of the flights 5 resembles that of the threads of a screw, which is what pushes material along the length of the shaft 8. The distance between corresponding points on consecutive flights 5 is typically called the pitch 10, which may vary along the length of the auger, depending on the application. Several auger features may be tailored to transfer different types of materials in different applications; such features include radius 12, which is the distance 12 from the center of the shaft 8 to the edge of a flight 5, pitch 10, and the existence of openings 14 in the flights 5. The ratio of pitch to diameter may be considered, depending on, for example, whether materials are only conveyed, or conveyed and mixed, or conveyed and packed/compressed. FIG. 2 is another example of an auger, which does not have openings in the flights 20. Typically, the amount of material to be moved per unit time determines the diameter of the auger; a larger radius generally moves more material. FIG. 3 illustrates an example of two augers 30, 40 housed in the same trough 45, where the flights 42 do not have openings, but instead include cuts 44. The cut depth 46 is the flight height 41 minus the distance from the outer surface of the shaft 48 to the bottom 43 of the cut 44. Housing augers in a trough 45 is common. The clearance between the trough 45 and the auger flights 42 may vary depending on the type of material conveyed. FIG. 4 is an example of an auger including flights 74a, 74b, 74c that have cuts 70 and folds 72. Cut flights are generally employed when the pitch is less than the diameter of the auger. The cuts may reduce the tendency of the material conveyed with such a design to compress between the flights rather than be pushed along by the auger. Auger characteristics such as pitch, flight height, trough clearance, and the existence, size, and shape of any openings, cuts, and folds in the flights may depend on the type of material processed and whether things such as mixing, agitation, and pressure/packing/compression at an outlet (e.g., in an extrusion application) are desired.
Significant costs are incurred because of the need to transport goods across the United States and internationally via truck, rail, air, and ship. Beneath certain maximum weight limits, the costs of transportation are often calculated per unit volume, or per container, rather than per unit weight. For example, when transporting via train, the cost may be calculated per railcar, as long as the weight of the goods in a single railcar stays beneath a certain maximum. Thus, there is a great cost incentive for transporters of goods to maximize the use of space when transporting. Further, even small per unit volume or per container cost savings may be significant because the total volume of goods transported is often large enough to bring about huge overall savings.
Thus, it would be desirable to have an improved method of loading bulk materials into a railcar that maximizes railcar capacity by increasing the density of materials within the railcar and, therefore, reduces transportation costs.